The invention relates to an x-ray diagnostic generator for the purpose of fluoroscopy and photography comprising an image intensifier, an installation for regulating the dose rate during fluoroscopy, an automatic exposure timer and a function generator to which a signal is supplied corresponding to the respective fluoroscopy-x-ray tube voltage, said function generator forming from said signal an output signal controlling the adjustment means for the photographic exposure-x-ray tube voltage, and wherein the characteristic of the photographic exposure voltage is programmed as a function of the fluoroscopy voltage.
An x-ray diagnostic generator of this type is described in the U.S. Pat. No. 3,991,314. In the case of this x-ray diagnostic generator, the change in the x-ray tube voltage and in the x-ray tube current proceeds by means of the fluoroscopy regulating installation in accordance with a predetermined function for effecting the change in the dose rate. From the respective fluoroscopy-x-ray tube voltage, the photographic exposure-x-ray tube voltage automatically results during the transition to a photographic mode; i.e., this voltage need not be individually adjusted by hand. The known x-ray diagnostic generator is thus very simple in its operation.
It has been observed that in practice the automatically adjusted photographic exposure-x-ray tube voltage is not always optimal. For instance, it is sometimes desirable to produce particularly high-contrast-x-ray photographs with a low x-ray tube voltage, or to produce photographs of short duration with a high x-ray tube voltage.